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. 2009 Apr 22;284(26):17835–17845. doi: 10.1074/jbc.M109.011502

FIGURE 7.

FIGURE 7.

Phenotypic analysis of chimeric DsbA. a, primary structure of EcDsbA, NmDsbA1, and NmDsbA2. Residues comprising the thioredoxin domain of EcDsbA are underlined. Residues that make contacts to the peptide substrate in the crystal structure of the complex are highlighted (*). b–e, phenotypic assays on dsbA− E. coli (JCB571) complemented with different DsbA proteins. b, JCB571 alone (lane 3), JCB571 complemented with EcDsbA in pTrc99A as a positive control (lane 4), and JCB571 complemented with EcTDNmDsbA1α (lane 1) or EcTDNmDsbA2α (lane 2) were able to grow on LB agar without DTT, indicating that each of the cell lines was viable. c, the same cell lines were tested for growth on LB agar containing 15 mm DTT and 1 mm isopropyl 1-thio-β-d-galactopyranoside to induce DsbA expression. Each of the cell lines that had been complemented with the DsbA proteins grew, whereas JCB571 did not, indicating that each construct expressed an active DsbA. d, neither JCB571 (zone 2) nor JCB571 complemented with EcTDNmDsbA1α (zone 3) was motile. In contrast, the positive control (JCB571 complemented with EcDsbA) (zone 1) was motile. e, both the positive control strain (zone 1) and JCB571 complemented with EcTDNmDsbA2α (zone 3) were motile, whereas JCB571 (zone 2) was not.